There's a fourth thing they provide that is less easy to come by, and that's the brand. If you want to find old schoolmates you go to friendsreunited.com, if you want to search the internet you go to google.com, if you want to meet up with people in your area, you go to meetup.com. I think that's what they believe they're selling, that draw, that ability to get random new people to come along and show an interest in your group. I think you're absolutely right though, getting them to sell meetup details to corporate sponsors would be a much better way for them to make money. I suppose you could do that yourself as an organiser, go out and seek some company who's willing to come along to your meetup and pay you (free bar, mmm) for the privelidge of advertising at you. But that's just silly, why would you bother with all the hassle just to meet some new friends?